/* eslint-disable no-cond-assign */
(function(mod) {
  mod(require('codemirror'));
})(function(CodeMirror) {
  'use strict';

  const HINT_ELEMENT_CLASS = 'CodeMirror-hint';
  const ACTIVE_HINT_ELEMENT_CLASS = 'CodeMirror-hint-active';

  // This is the old interface, kept around for now to stay
  // backwards-compatible.
  CodeMirror.showHint = function(cm, getHints, options) {
    if (!getHints) return cm.showHint(options);
    if (options && options.async) getHints.async = true;
    const newOpts = { hint: getHints };
    if (options) for (const prop in options) newOpts[prop] = options[prop];
    return cm.showHint(newOpts);
  };

  CodeMirror.defineExtension('showHint', function(options) {
    options = parseOptions(this, this.getCursor('start'), options);
    const selections = this.listSelections();
    if (selections.length > 1) return;
    // By default, don't allow completion when something is selected.
    // A hint function can have a `supportsSelection` property to
    // indicate that it can handle selections.
    if (this.somethingSelected()) {
      if (!options.hint.supportsSelection) return;
      // Don't try with cross-line selections
      for (let i = 0; i < selections.length; i++) { if (selections[i].head.line !== selections[i].anchor.line) return; }
    }

    if (this.state.completionActive) this.state.completionActive.close();
    const completion = this.state.completionActive = new Completion(this, options);
    if (!completion.options.hint) return;

    CodeMirror.signal(this, 'startCompletion', this);
    completion.update(true);
  });

  CodeMirror.defineExtension('closeHint', function() {
    if (this.state.completionActive) this.state.completionActive.close();
  });

  function Completion(cm, options) {
    this.cm = cm;
    this.options = options;
    this.widget = null;
    this.debounce = 0;
    this.tick = 0;
    this.startPos = this.cm.getCursor('start');
    this.startLen = this.cm.getLine(this.startPos.line).length - this.cm.getSelection().length;

    if (this.options.updateOnCursorActivity) {
      const self = this;
      cm.on('cursorActivity', this.activityFunc = function() { self.cursorActivity(); });
    }
  }

  const requestAnimationFrame = window.requestAnimationFrame || function(fn) {
    return setTimeout(fn, 1000 / 60);
  };
  const cancelAnimationFrame = window.cancelAnimationFrame || clearTimeout;

  Completion.prototype = {
    close: function() {
      if (!this.active()) return;
      this.cm.state.completionActive = null;
      this.tick = null;
      if (this.options.updateOnCursorActivity) {
        this.cm.off('cursorActivity', this.activityFunc);
      }
      if (this.widget && this.data) {
        CodeMirror.signal(this.data, 'close');
      }
      if (this.widget) this.widget.close();
      CodeMirror.signal(this.cm, 'endCompletion', this.cm);
    },

    active: function() {
      return this.cm.state.completionActive === this;
    },

    pick: function(data, i) {
      const completion = data.list[i];
      const self = this;
      this.cm.operation(function() {
        if (completion.hint) { completion.hint(self.cm, data, completion); } else {
          self.cm.replaceRange(getText(completion), completion.from || data.from,
            completion.to || data.to, 'complete');
          if (self.options.pickCallback) self.options.pickCallback();
        }
        CodeMirror.signal(data, 'pick', completion);
        self.cm.scrollIntoView();
      });
      if (this.options.closeOnPick) {
        this.close();
      }
    },

    cursorActivity: function() {
      if (this.debounce) {
        cancelAnimationFrame(this.debounce);
        this.debounce = 0;
      }

      let identStart = this.startPos;
      if (this.data) {
        identStart = this.data.from;
      }

      const pos = this.cm.getCursor();
      const line = this.cm.getLine(pos.line);
      if (pos.line !== this.startPos.line || line.length - pos.ch !== this.startLen - this.startPos.ch ||
          pos.ch < identStart.ch || this.cm.somethingSelected() ||
          (!pos.ch || this.options.closeCharacters.test(line.charAt(pos.ch - 1)))) {
        this.close();
      } else {
        const self = this;
        this.debounce = requestAnimationFrame(function() { self.update(); });
        if (this.widget) this.widget.disable();
      }
    },

    update: function(first) {
      if (this.tick == null) return;
      const self = this;
      const myTick = ++this.tick;
      fetchHints(this.options.hint, this.cm, this.options, function(data) {
        if (self.tick === myTick) self.finishUpdate(data, first);
      });
    },

    finishUpdate: function(data, first) {
      if (this.data) CodeMirror.signal(this.data, 'update');

      const picked = (this.widget && this.widget.picked) || (first && this.options.completeSingle);
      if (this.widget) this.widget.close();

      this.data = data;

      if (data && data.list.length) {
        if (picked && data.list.length === 1) {
          this.pick(data, 0);
        } else {
          this.widget = new Widget(this, data);
          CodeMirror.signal(data, 'shown');
        }
      }
    }
  };

  function parseOptions(cm, pos, options) {
    const editor = cm.options.hintOptions;
    const out = {};
    for (const prop in defaultOptions) out[prop] = defaultOptions[prop];
    if (editor) {
      for (const prop in editor) { if (editor[prop] !== undefined) out[prop] = editor[prop]; }
    }
    if (options) {
      for (const prop in options) { if (options[prop] !== undefined) out[prop] = options[prop]; }
    }
    if (out.hint.resolve) out.hint = out.hint.resolve(cm, pos);
    return out;
  }

  function getText(completion) {
    if (typeof completion === 'string') return completion;
    else return completion.text;
  }

  function buildKeyMap(completion, handle) {
    const baseMap = {
      Up: function() { handle.moveFocus(-1); },
      Down: function() { handle.moveFocus(1); },
      PageUp: function() { handle.moveFocus(-handle.menuSize() + 1, true); },
      PageDown: function() { handle.moveFocus(handle.menuSize() - 1, true); },
      Home: function() { handle.setFocus(0); },
      End: function() { handle.setFocus(handle.length - 1); },
      Enter: handle.pick,
      Tab: handle.pick,
      Esc: handle.close
    };

    const mac = /Mac/.test(navigator.platform);

    if (mac) {
      baseMap['Ctrl-P'] = function() { handle.moveFocus(-1); };
      baseMap['Ctrl-N'] = function() { handle.moveFocus(1); };
    }

    const custom = completion.options.customKeys;
    const ourMap = custom ? {} : baseMap;
    function addBinding(key, val) {
      let bound;
      if (typeof val !== 'string') {
        bound = function(cm) { return val(cm, handle); };
      } else if (baseMap.hasOwnProperty(val)) { bound = baseMap[val]; } else { bound = val; }
      ourMap[key] = bound;
    }
    if (custom) {
      for (const key in custom) {
        if (custom.hasOwnProperty(key)) { addBinding(key, custom[key]); }
      }
    }
    const extra = completion.options.extraKeys;
    if (extra) {
      for (const key in extra) {
        if (extra.hasOwnProperty(key)) { addBinding(key, extra[key]); }
      }
    }
    return ourMap;
  }

  function getHintElement(hintsElement, el) {
    while (el && el !== hintsElement) {
      if (el.nodeName.toUpperCase() === 'LI' && el.parentNode === hintsElement) return el;
      el = el.parentNode;
    }
  }

  function Widget(completion, data) {
    this.id = 'cm-complete-' + Math.floor(Math.random(1e6));
    this.completion = completion;
    this.data = data;
    this.picked = false;
    const widget = this;
    const cm = completion.cm;
    const ownerDocument = cm.getInputField().ownerDocument;
    const parentWindow = ownerDocument.defaultView || ownerDocument.parentWindow;

    const hints = this.hints = ownerDocument.createElement('ul');
    hints.setAttribute('role', 'listbox');
    hints.setAttribute('aria-expanded', 'true');
    hints.id = this.id;
    const theme = completion.cm.options.theme;
    hints.className = 'CodeMirror-hints ' + theme;
    this.selectedHint = data.selectedHint || 0;

    const completions = data.list;
    for (let i = 0; i < completions.length; ++i) {
      const elt = hints.appendChild(ownerDocument.createElement('li'));
      const cur = completions[i];
      let className = HINT_ELEMENT_CLASS + (i !== this.selectedHint ? '' : ' ' + ACTIVE_HINT_ELEMENT_CLASS);
      if (cur.className != null) className = cur.className + ' ' + className;
      elt.className = className;
      if (i === this.selectedHint) elt.setAttribute('aria-selected', 'true');
      elt.id = this.id + '-' + i;
      elt.setAttribute('role', 'option');
      if (cur.render) cur.render(elt, data, cur);
      else elt.appendChild(ownerDocument.createTextNode(cur.displayText || getText(cur)));
      elt.hintId = i;
    }

    const container = completion.options.container || ownerDocument.body;
    let pos = cm.cursorCoords(completion.options.alignWithWord ? data.from : null);
    let left = pos.left;
    let top = pos.bottom;
    let below = true;
    let offsetLeft = 0;
    let offsetTop = 0;
    if (container !== ownerDocument.body) {
      // We offset the cursor position because left and top are relative to the offsetParent's top left corner.
      const isContainerPositioned = ['absolute', 'relative', 'fixed'].indexOf(parentWindow.getComputedStyle(container).position) !== -1;
      const offsetParent = isContainerPositioned ? container : container.offsetParent;
      const offsetParentPosition = offsetParent.getBoundingClientRect();
      const bodyPosition = ownerDocument.body.getBoundingClientRect();
      offsetLeft = (offsetParentPosition.left - bodyPosition.left - offsetParent.scrollLeft);
      offsetTop = (offsetParentPosition.top - bodyPosition.top - offsetParent.scrollTop);
    }
    hints.style.left = (left - offsetLeft) + 'px';
    hints.style.top = (top - offsetTop) + 'px';

    // If we're at the edge of the screen, then we want the menu to appear on the left of the cursor.
    const winW = parentWindow.innerWidth || Math.max(ownerDocument.body.offsetWidth, ownerDocument.documentElement.offsetWidth);
    const winH = parentWindow.innerHeight || Math.max(ownerDocument.body.offsetHeight, ownerDocument.documentElement.offsetHeight);
    container.appendChild(hints);
    cm.getInputField().setAttribute('aria-autocomplete', 'list');
    cm.getInputField().setAttribute('aria-owns', this.id);
    cm.getInputField().setAttribute('aria-activedescendant', this.id + '-' + this.selectedHint);

    let box = completion.options.moveOnOverlap ? hints.getBoundingClientRect() : new DOMRect();
    const scrolls = completion.options.paddingForScrollbar ? hints.scrollHeight > hints.clientHeight + 1 : false;

    // Compute in the timeout to avoid reflow on init
    let startScroll;
    setTimeout(function() { startScroll = cm.getScrollInfo(); });

    const overlapY = box.bottom - winH;
    if (overlapY > 0) {
      const height = box.bottom - box.top;
      const curTop = pos.top - (pos.bottom - box.top);
      if (curTop - height > 0) { // Fits above cursor
        hints.style.top = (top = pos.top - height - offsetTop) + 'px';
        below = false;
      } else if (height > winH) {
        hints.style.height = (winH - 5) + 'px';
        hints.style.top = (top = pos.bottom - box.top - offsetTop) + 'px';
        const cursor = cm.getCursor();
        if (data.from.ch !== cursor.ch) {
          pos = cm.cursorCoords(cursor);
          hints.style.left = (left = pos.left - offsetLeft) + 'px';
          box = hints.getBoundingClientRect();
        }
      }
    }
    let overlapX = box.right - winW;
    if (scrolls) overlapX += cm.display.nativeBarWidth;
    if (overlapX > 0) {
      if (box.right - box.left > winW) {
        hints.style.width = (winW - 5) + 'px';
        overlapX -= (box.right - box.left) - winW;
      }
      hints.style.left = (left = Math.max(pos.left - overlapX - offsetLeft, 0)) + 'px';
    }
    if (scrolls) {
      for (let node = hints.firstChild; node; node = node.nextSibling) { node.style.paddingRight = cm.display.nativeBarWidth + 'px'; }
    }

    cm.addKeyMap(this.keyMap = buildKeyMap(completion, {
      moveFocus: function(n, avoidWrap) { widget.changeActive(widget.selectedHint + n, avoidWrap); },
      setFocus: function(n) { widget.changeActive(n); },
      menuSize: function() { return widget.screenAmount(); },
      length: completions.length,
      close: function() { completion.close(); },
      pick: function() { widget.pick(); },
      data: data
    }));

    if (completion.options.closeOnUnfocus) {
      let closingOnBlur;
      cm.on('blur', this.onBlur = function() { closingOnBlur = setTimeout(function() { completion.close(); }, 100); });
      cm.on('focus', this.onFocus = function() { clearTimeout(closingOnBlur); });
    }

    cm.on('scroll', this.onScroll = function() {
      const curScroll = cm.getScrollInfo();
      const editor = cm.getWrapperElement().getBoundingClientRect();
      if (!startScroll) startScroll = cm.getScrollInfo();
      const newTop = top + startScroll.top - curScroll.top;
      let point = newTop - (parentWindow.pageYOffset || (ownerDocument.documentElement || ownerDocument.body).scrollTop);
      if (!below) point += hints.offsetHeight;
      if (point <= editor.top || point >= editor.bottom) return completion.close();
      hints.style.top = newTop + 'px';
      hints.style.left = (left + startScroll.left - curScroll.left) + 'px';
    });

    CodeMirror.on(hints, 'dblclick', function(e) {
      const t = getHintElement(hints, e.target || e.srcElement);
      if (t && t.hintId != null) { widget.changeActive(t.hintId); widget.pick(); }
    });

    CodeMirror.on(hints, 'click', function(e) {
      const t = getHintElement(hints, e.target || e.srcElement);
      if (t && t.hintId != null) {
        widget.changeActive(t.hintId);
        if (completion.options.completeOnSingleClick) widget.pick();
      }
    });

    CodeMirror.on(hints, 'mousedown', function() {
      setTimeout(function() { cm.focus(); }, 20);
    });

    // The first hint doesn't need to be scrolled to on init
    const selectedHintRange = this.getSelectedHintRange();
    if (selectedHintRange.from !== 0 || selectedHintRange.to !== 0) {
      this.scrollToActive();
    }

    CodeMirror.signal(data, 'select', completions[this.selectedHint], hints.childNodes[this.selectedHint]);
    return true;
  }

  Widget.prototype = {
    close: function() {
      if (this.completion.widget !== this) return;
      this.completion.widget = null;
      if (this.hints.parentNode) this.hints.parentNode.removeChild(this.hints);
      this.completion.cm.removeKeyMap(this.keyMap);
      const input = this.completion.cm.getInputField();
      input.removeAttribute('aria-activedescendant');
      input.removeAttribute('aria-owns');

      const cm = this.completion.cm;
      if (this.completion.options.closeOnUnfocus) {
        cm.off('blur', this.onBlur);
        cm.off('focus', this.onFocus);
      }
      cm.off('scroll', this.onScroll);
    },

    disable: function() {
      this.completion.cm.removeKeyMap(this.keyMap);
      const widget = this;
      this.keyMap = { Enter: function() { widget.picked = true; } };
      this.completion.cm.addKeyMap(this.keyMap);
    },

    pick: function() {
      this.completion.pick(this.data, this.selectedHint);
    },

    changeActive: function(i, avoidWrap) {
      if (i >= this.data.list.length) { i = avoidWrap ? this.data.list.length - 1 : 0; } else if (i < 0) { i = avoidWrap ? 0 : this.data.list.length - 1; }
      if (this.selectedHint === i) return;
      let node = this.hints.childNodes[this.selectedHint];
      if (node) {
        node.className = node.className.replace(' ' + ACTIVE_HINT_ELEMENT_CLASS, '');
        node.removeAttribute('aria-selected');
      }
      node = this.hints.childNodes[this.selectedHint = i];
      node.className += ' ' + ACTIVE_HINT_ELEMENT_CLASS;
      node.setAttribute('aria-selected', 'true');
      this.completion.cm.getInputField().setAttribute('aria-activedescendant', node.id);
      this.scrollToActive();
      CodeMirror.signal(this.data, 'select', this.data.list[this.selectedHint], node);
    },

    scrollToActive: function() {
      const selectedHintRange = this.getSelectedHintRange();
      const node1 = this.hints.childNodes[selectedHintRange.from];
      const node2 = this.hints.childNodes[selectedHintRange.to];
      const firstNode = this.hints.firstChild;
      if (node1.offsetTop < this.hints.scrollTop) { this.hints.scrollTop = node1.offsetTop - firstNode.offsetTop; } else if (node2.offsetTop + node2.offsetHeight > this.hints.scrollTop + this.hints.clientHeight) { this.hints.scrollTop = node2.offsetTop + node2.offsetHeight - this.hints.clientHeight + firstNode.offsetTop; }
    },

    screenAmount: function() {
      return Math.floor(this.hints.clientHeight / this.hints.firstChild.offsetHeight) || 1;
    },

    getSelectedHintRange: function() {
      const margin = this.completion.options.scrollMargin || 0;
      return {
        from: Math.max(0, this.selectedHint - margin),
        to: Math.min(this.data.list.length - 1, this.selectedHint + margin)
      };
    }
  };

  function applicableHelpers(cm, helpers) {
    if (!cm.somethingSelected()) return helpers;
    const result = [];
    for (let i = 0; i < helpers.length; i++) { if (helpers[i].supportsSelection) result.push(helpers[i]); }
    return result;
  }

  function fetchHints(hint, cm, options, callback) {
    if (hint.async) {
      hint(cm, callback, options);
    } else {
      const result = hint(cm, options);
      if (result && result.then) result.then(callback);
      else callback(result);
    }
  }

  function resolveAutoHints(cm, pos) {
    const helpers = cm.getHelpers(pos, 'hint');
    let words;
    if (helpers.length) {
      const resolved = function(cm, callback, options) {
        const app = applicableHelpers(cm, helpers);
        function run(i) {
          if (i === app.length) return callback(null);
          fetchHints(app[i], cm, options, function(result) {
            if (result && result.list.length > 0) callback(result);
            else run(i + 1);
          });
        }
        run(0);
      };
      resolved.async = true;
      resolved.supportsSelection = true;
      return resolved;
    } else if (words = cm.getHelper(cm.getCursor(), 'hintWords')) {
      return function(cm) { return CodeMirror.hint.fromList(cm, { words: words }); };
    } else if (CodeMirror.hint.anyword) {
      return function(cm, options) { return CodeMirror.hint.anyword(cm, options); };
    } else {
      return function() {};
    }
  }

  CodeMirror.registerHelper('hint', 'auto', {
    resolve: resolveAutoHints
  });

  CodeMirror.registerHelper('hint', 'fromList', function(cm, options) {
    const cur = cm.getCursor();
    const token = cm.getTokenAt(cur);
    let term;
    let from = CodeMirror.Pos(cur.line, token.start);
    const to = cur;
    if (token.start < cur.ch && /\w/.test(token.string.charAt(cur.ch - token.start - 1))) {
      term = token.string.substr(0, cur.ch - token.start);
    } else {
      term = '';
      from = cur;
    }
    const found = [];
    for (let i = 0; i < options.words.length; i++) {
      const word = options.words[i];
      if (word.slice(0, term.length) === term) { found.push(word); }
    }

    if (found.length) return { list: found, from: from, to: to };
  });

  CodeMirror.commands.autocomplete = CodeMirror.showHint;

  const defaultOptions = {
    hint: CodeMirror.hint.auto,
    completeSingle: true,
    alignWithWord: true,
    closeCharacters: /[\s()\[\]{};:>,]/,
    closeOnPick: true,
    closeOnUnfocus: true,
    updateOnCursorActivity: true,
    completeOnSingleClick: true,
    container: null,
    customKeys: null,
    extraKeys: null,
    paddingForScrollbar: true,
    moveOnOverlap: true
  };
  CodeMirror.defineOption('hintOptions', null);
});
